Impeller structure

ABSTRACT

An impeller structure includes a hub, a plurality of blades, and a plurality of reinforcing ribs. The blades are extended from the hub, and the reinforcing ribs are disposed annularly and separately between the blades. The strength of the impeller structure is improved by the reinforcing ribs, and the interference between the inner and outer flow fields of the blades is reduced by the reinforcing ribs. Also, a fan including above-mentioned impeller structure is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Taiwan Patent Application No.100110236, filed on Mar. 25, 2011, the entirety of which is incorporatedby reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an impeller structure, and in particular to animpeller structure with reinforcing ribs.

2. Description of the Related Art

In general, large-scale fans used in air-conditioning systems have alarge size and high rotating speed. For strength purposes, one solutionfor impellers of large-scale fans are that they are made from metal.However, due to very high precision requirements for the mold for makinga metal impeller, much labor and resources are needed, thus increasingdevelopment costs. Further, the consistency of the quality of the metalimpeller made by a mold is not stable. Also, the cost of metal is high.

Another solution is for the impeller to be made from plastic. However,the strength of plastic may be inefficient. For example, under hightemperatures at high rotation speeds, a plastic impeller may deform moreeasily. Please refer to FIG. 1. To improve the strength of the impeller100, a fixed ring 120 is disposed on ends of blades 110. However, theflow field of the impeller structure is completely separated by thefixed ring 120, and the flow field within the fixed ring 120 interfereswith the flow field on the outside of the fixed ring 120. Note that theweight of the impeller 100 is greatly increased due to the fixed ring120.

BRIEF SUMMARY OF THE INVENTION

To solve the problems of the prior art, the object of the invention isto provide an impeller structure and a fan. The fan includes theimpeller structure. The impeller structure includes a plurality ofreinforcing ribs and a plurality of blades. The reinforcing ribs aredisposed between the blades, and located between side edges andconnecting edges of the blades, and thus the balance of the blades isimproved without sacrificing strength thereof, and the interference ofthe flow fields is reduced.

For the above objective, the impeller structure includes a hub, aplurality of blades, and a plurality of reinforcing ribs. The hub isrotated about a rotation axis, and has an outer surface. The blades areextended from the outer surface. Each of the blades has a windwardsurface and a leeward surface opposite to the windward surface. Further,each of the blades has a side edge, a connecting edge opposite to theside edge, a trailing edge, and a leading edge opposite to the trailingedge thereof. The side edge is distant from the hub, and the connectingedge is connected to the hub. The reinforcing ribs are annularly andseparately disposed on the blades, and located between the side edgesand the connecting edges of the blades. An end of one of the reinforcingribs is connected to the windward surface of one of the blades, and theother end of the one of the reinforcing ribs is connected to a leewardsurface of an adjacent blade. Moreover, the end of the one of thereinforcing ribs is adjacent to the leading edge of the blade and isdistant from the trailing edge of the blade. The other end of the one ofthe reinforcing ribs is adjacent to a trailing edge of the adjacentblade and is distant from a leading edge of the adjacent blade.

For the above objective, the impeller structure includes a hub, aplurality of sub-blades, a separation ring, a plurality of blades, and aplurality of reinforcing ribs. The hub is rotated about a rotation axis,and has an outer surface. The sub-blades are radiantly extended from theouter surface of the hub, respectively. The separation ring is disposedon the end of the sub-blades. The blades are extended from theseparation ring opposite to the sub-blades. Each of the blades has awindward surface and a leeward surface opposite to the windward surface.Further, each of the blades has a side edge, a connecting edge oppositeto the side edge, a trailing edge, and a leading edge opposite to thetrailing edge. The side edge is distant from the separation ring, andthe connecting edge is connected to the separation ring. The reinforcingribs are annularly and separately disposed on the blades, and locatedbetween the side edges and the connecting edges of the blades. An end ofone of the reinforcing ribs is connected to the windward surface of oneof the blades, and the other end of the one of the reinforcing ribs isconnected to a leeward surface of an adjacent blade. Moreover, the endof the one of the reinforcing ribs is adjacent to the leading edge ofthe blade and is distant from the trailing edge of the blade. The otherend of the one of the reinforcing ribs is adjacent to a trailing edge ofthe adjacent blade and is distant from a leading edge of the adjacentblade.

In conclusion, by the structure of the reinforcing ribs and the blades,the strength of the impeller structure can be improved. Thus, theimpeller structure may be made by plastic, and the cost of the impellerstructure can be decreased. Moreover, the manufacturing of the impellerstructure is easier and more precise. The weight of the blades isreduced due to the small size and light weight of the reinforcing ribs,and thus the balance of the rotation of the impeller structure isimproved. In addition, the blades are not completely separated into twoparts by the reinforcing ribs, and thus the interference between theinner and outer flow fields of the impeller structure can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 is a perspective view of an impeller structure of the prior art;

FIG. 2 is a perspective view of an impeller structure of a firstembodiment of the invention;

FIG. 3 is a top view of the impeller structure of the first embodimentof the invention;

FIG. 4 is a side view of the impeller structure of the first embodimentof the invention;

FIG. 5 is a cross-sectional view of the reinforcing rib along AA line ofFIG. 4;

FIG. 6 is a perspective view of an impeller structure of a secondembodiment of the invention; and

FIG. 7 is a top view of the impeller structure of the second embodimentof the invention.

DETAILED DESCRIPTION OF THE INVENTION

Please refer to FIG. 2 to FIG. 4. FIG. 2 is a perspective view of animpeller structure of a first embodiment of the invention. FIG. 3 is atop view of the impeller structure of the first embodiment of theinvention. FIG. 4 is a side view of the impeller structure of the firstembodiment of the invention. The impeller structure 200 may be connectedto a motor (not shown in the figures) to form a fan. The impellerstructure 200 is driven by the motor to generate an air flow. It isnoted that the impeller structure can be used in a fan.

The impeller structure 200 may be made from plastic. The impellerstructure 200 includes a hub 210, a plurality of blades 220, and aplurality of reinforcing ribs 230. The hub 210 is circular disc shapedwith a hollow structure. The hub 210 is disposed on the motor, anddriven by the motor to rotate about a rotation axis AX1. Further, thehub 210 has an outer surface 211.

Each of the blades 220 is a thin stripped structure, and may be madefrom plastic. The blades 220 are radiantly extended from the outersurface 211. There is a separation space S1 between two of the blades220. Each of the blades 220 has a windward surface 221 and a leewardsurface 222. The windward surface 221 and the leeward surface 222 arelocated at two opposite sides of the blade 220, and occupy most of thesurface area of the blade 220. The windward surface 221 faces an areawhere the air flow flows into the impeller structure 200, and theleeward surface 222 faces an area where the air flow flows out of theimpeller structure 200.

Each of the blades 220 has a side edge 223, a connecting edge 224, atrailing edge 225, and a leading edge 226. The windward surface 221 andthe leeward surface 222 are surrounded by the side edge 223, theconnecting edge 224, the trailing edge 225, and the leading edge 226.The side edge 223 and the connecting edge 224 are disposed on twoopposite sides of the blade 220. The side edge 223 is distant from hub210, and the connecting edge 224 is connected to the hub 210.

The trailing edge 225 corresponds to an area where the air flow flowsinto the impeller structure 200. The leading edge 226 corresponds to anarea where the air flow flows out of the impeller structure 200. Thetrailing edge 225 and the leading edge 226 are disposed on two oppositesides of the blade 220, and are connected to the side edge 223 and theconnecting edge 224. As shown in FIG. 4, the leading edge 226 of theblade 220 is near a trailing edge 225 a of an adjacent blade 220 a, andis distant from a leading edge 226 a of the adjacent blade 220 a.

The reinforcing ribs 230 are annularly and separately disposed on theblades 220, and are located between the side edges 223 and theconnecting edges 224 of the blades 220. An end of the reinforcing rib230 is connected to the windward surface 221 of the blade 220, and theother end of the reinforcing ribs 230 is connected to the leewardsurface 222 a of the adjacent blade 220 a. The end of the reinforcingrib 230 connected to the windward surface 221 is adjacent to the leadingedge 226, and is distant from trailing edge 225. The other end ofreinforcing rib 230 connected to the leeward surface 222 a of theadjacent blade 220 a is adjacent to the trailing edge 225 a, and isdistant from the leading edge 226 a of the adjacent blade 220 a.

As shown in FIG. 4, the blade 220 has a wing-tip chord length W2 betweenthe trailing edge 225 and the leading edge 226. The width W1 of thereinforcing rib 230 is smaller than half of the wing-tip chord length W2of the blade 220. In the embodiment, the width W1 of the reinforcing rib230 is smaller than one-third the wing-tip chord length W2 of the blade220.

As shown in FIG. 3, the reinforcing rib 230 is perpendicular to theblade 220, and the reinforcing rib 230 is connected to the blade 220 atan area from one-third to two-third of the length L1, which is from theside edge 223 to the connecting edge 224, of the blade 220. Thus, thestrength of the blade 220 can be improved. Moreover, the reinforcing rib230 is arranged along a circular track, wherein the rotation axis AX1 isat the center of the circular track. By the above arrangement, theinterference of the flow field of the air flow is decreased by thereinforcing rib 230.

As shown in FIG. 4, the separation space S1 is between the windwardsurface 221 of the blade 220 and the leeward surface 222 a of the blade220 a. The reinforcing rib 230 is extended along an extension directionD1, and the air flow flows into the impeller structure 200 along an airintake direction D2. The extension direction D1 is 45 degrees to the airintake direction D2 or the rotation axis AX1, and thus the flowresistance generated by the reinforcing rib 230 can be decreased.

The reinforcing rib 230 and the reinforcing rib 230 a are connected totwo opposite sides of the blade 220, and the extensions of thereinforcing rib 230 and the reinforcing rib 230 a are not overlapped orcrossed along the extension direction D1 or the air intake direction D2.Thus, the separation space S1 between the blade 220 and the adjacentblade 220 a are not completely separated into an inner zone Z1 and anouter zone Z2 (as shown in FIG. 3) by the reinforcing rib 230. Namely,the inner zone Z1 and the outer zone Z2 between the blade 220 and theblade 220 a are communicated to each other. The flow field of the airflow will not completely be separated by the reinforcing rib 230 abetween the blade 220 and the blade 220 a, and the interference betweenan inner flow field in the inner zone Z1 and an outer flow field in theouter zone Z2 can be reduced.

Please also refer to FIG. 5, which is a cross-sectional view of thereinforcing rib 230 along AA line of FIG. 4. The extension direction D1(as shown in FIG. 4) is perpendicular to the cross section of thereinforcing rib 230. In the embodiment, the cross section of thereinforcing rib 230 is rectangular with rounded ends. The ends of thereinforcing ribs 230 have a conduction current function. Thus, when theimpeller structure 200 is rotated, the air flow flows through the endsof the reinforcing ribs 230 smoothly. However, the shape of the crosssection of the reinforcing rib 230 is not limited. In the otherembodiment, the shape of the cross section of the reinforcing rib 230may be rectangular, an ellipse, a trapezoid or wing shaped.

Please refer to FIG. 6 and FIG. 7. FIG. 6 is a perspective view of animpeller structure 200 a of a second embodiment of the invention. FIG. 7is a top view of the impeller structure 200 a of the second embodimentof the invention. The differences between the second embodiment and thefirst embodiment are described as following. The impeller structure 200a further includes a plurality of sub-blades 240 and a separation ring250. The sub-blades 240 are radiantly extended from the outer surface211 of the hub 210. The separation ring 250 is a ring structure aroundthe hub 210. The separation ring 250 is disposed on the ends of thesub-blades 240. The blades 220 are extended from the separation ring250. In the other words, the sub-blades 240 and the blades 220 aredisposed on two opposite sides of the separation ring 250. Moreover, thelength of the sub-blade 240 is smaller than the length of the blade 220,and the number of the sub-blades 240 is greater than the number ofblades 220.

In the embodiment, the hub 210 is pivoted on a base (not shown in thefigures), and a guide tube (not shown in the figures) is connected tothe separation ring 250. An air flow is transmitted to the sub-blade 240within the separation ring 250 by the guide tube to drive the sub-blade240 to rotate. When the sub-blades 240 are rotated, the blades 220 ofthe impeller structure 200 a are rotated due to the sub-blades 240, andthe blades 220 drive an air flow, outside the guide tube, flowing.

In conclusion, by the structure of the reinforcing ribs and the blades,the strength of the impeller structure can be improved. Thus, theimpeller structure can be made by plastic, and the cost of the impellerstructure can be decreased. Moreover, the manufacturing of the impellerstructure is easier and more precise. The weight of the blades isreduced due to the small size and light weight of the reinforcing ribs,and thus the balance of the rotation of the impeller structure isimproved. In addition, the blades are not completely separated into twoparts by the reinforcing ribs, and thus the interference between theinner and outer flow fields of the impeller structure can be reduced.

While the invention has been described by way of example and in terms ofpreferred embodiment, it is to be understood that the invention is notlimited thereto. To the contrary, it is intended to cover variousmodifications and similar arrangements (as would be apparent to thoseskilled in the art). Therefore, the scope of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements.

1. An impeller structure, comprising: a hub, rotated about a rotationaxis, having an outer surface; a plurality of blades extended from theouter surface, wherein each of the blades has a windward surface and aleeward surface opposite to the windward surface, and each of the bladeshas a side edge, a connecting edge opposite to the side edge, a trailingedge, and a leading edge opposite to the trailing edge, wherein the sideedge is distant from the hub, and the connecting edge is connected tothe hub; and a plurality of reinforcing ribs, annularly and separatelydisposed on the blades, located between the side edges and theconnecting edges of the blades, wherein an end of one of the reinforcingribs is connected to the windward surface of one of the blades, and theother end of the one of the reinforcing ribs is connected to a leewardsurface of an adjacent blade, wherein the end of the one of thereinforcing ribs is adjacent to the leading edge of the blade and isdistant from the trailing edge of the blade, and the other end of theone of the reinforcing ribs is adjacent to a trailing edge of theadjacent blade and is distant from a leading edge of the adjacent blade.2. The impeller structure as claimed in claim 1, wherein the width ofeach of the reinforcing ribs is smaller than half of a wing-tip chordlength of each of the blades.
 3. The impeller structure as claimed inclaim 1, wherein the reinforcing rib is connected to the blade at anarea from one-third to two-third of the blade
 220. 4. The impellerstructure as claimed in claim 1, wherein the reinforcing ribs areperpendicular to the blades, respectively.
 5. The impeller structure asclaimed in claim 1, wherein the cross section of each of the reinforcingribs is rectangular, rectangular with rounded ends, an ellipse, atrapezoid, or wing shaped.
 6. The impeller structure as claimed in claim1, wherein the leading edge of the blade is near the trailing edge ofthe adjacent blade, and is distant from the leading edge of the adjacentblade.
 7. An impeller structure, comprising: a hub, rotated about arotation axis, having an outer surface; a plurality of sub-bladesradiantly extended from the outer surface of the hub, respectively; aseparation ring disposed on the end of the sub-blades; a plurality ofblades extended from the separation ring opposite to the sub-blades,wherein each of the blades has a windward surface and a leeward surfaceopposite to the windward surface, and each of the blades has a sideedge, a connecting edge opposite to the side edge, a trailing edge, anda leading edge opposite to the trailing edge, wherein the side edge isdistant from the separation ring, and the connecting edge is connectedto the separation ring; and a plurality of reinforcing ribs, annularlyand separately disposed on the blades, located between the side edgesand the connecting edges of the blades, wherein an end of one of thereinforcing ribs is connected to the windward surface of one of theblades, and the other end of the one of the reinforcing ribs isconnected to a leeward surface of an adjacent blade, and wherein the endof the one of the reinforcing ribs is adjacent to the leading edge ofthe blade and is distant from the trailing edge of the blade, and theother end of the one of the reinforcing ribs is adjacent to a trailingedge of the adjacent blade and is distant from a leading edge of theadjacent blade.
 8. The impeller structure as claimed in claim 7, whereinthe width of each of the reinforcing ribs is smaller than half of awing-tip chord length of each of the blades.
 9. The impeller structureas claimed in claim 7, wherein the reinforcing rib is connected to theblade at an area from one-third to two-third of the blade
 220. 10. Theimpeller structure as claimed in claim 7, wherein the reinforcing ribsare perpendicular to the blades, respectively.
 11. The impellerstructure as claimed in claim 7, wherein the cross section of each ofthe reinforcing ribs is rectangular, rectangular with rounded ends, anellipse, a trapezoid, or wing shaped.
 12. The impeller structure asclaimed in claim 7, wherein the leading edge of the blade is near thetrailing edge of the adjacent blade, and is distant from the leadingedge of the adjacent blade.
 13. The impeller structure as claimed inclaim 7, wherein the length of each of the sub-blades is smaller thanthe length of each of the blades, and the number of the sub-blades isgreater than the number of the blades.
 14. A fan, comprising an impellerstructure, the impeller structure comprising: a hub, rotated about arotation axis, having an outer surface; a plurality of blades extendedfrom the outer surface, wherein each of the blades has a windwardsurface and a leeward surface opposite to the windward surface, and eachof the blades has a side edge, a connecting edge opposite to the sideedge, a trailing edge, and a leading edge opposite to the trailing edge,wherein the side edge is distant from the hub, and the connecting edgeis connected to the hub; and a plurality of reinforcing ribs, annularlyand separately disposed on the blades, located between the side edgesand the connecting edges of the blades, wherein an end of one of thereinforcing ribs is connected to the windward surface of one of theblades, and the other end of the one of the reinforcing ribs isconnected to a leeward surface of an adjacent blade, wherein the end ofthe one of the reinforcing ribs is adjacent to the leading edge of theblade and is distant from the trailing edge of the blade, and the otherend of the one of the reinforcing ribs is adjacent to a trailing edge ofthe adjacent blade and is distant from a leading edge of the adjacentblade.
 15. The fan as claimed in claim 14, wherein the width of each ofthe reinforcing ribs is smaller than half of a wing-tip chord length ofeach of the blades.
 16. The fan as claimed in claim 14, wherein thereinforcing rib is connected to the blade at an area from one-third totwo-third of the blade.
 17. The fan as claimed in claim 14, wherein thereinforcing ribs are perpendicular to the blades, respectively.
 18. Thefan as claimed in claim 14, wherein the cross section of each of thereinforcing ribs is rectangular, rectangular with rounded ends, anellipse, a trapezoid, or wing shaped.
 19. The fan as claimed in claim14, wherein the leading edge of the blade is near the trailing edge ofthe adjacent blade, and is distant from the leading edge of the adjacentblade.